Smart circulation control instantaneous-heating storage heat exchanger

ABSTRACT

A smart circulation control instantaneous-heating storage heat exchanger includes a heat exchanger, a cold-water pipe, a hot-water pipe, an internal circulation pipe, and a control unit. The heat exchanger includes a storage space. The internal circulation pipe includes a two-way valve and a circulation pump. The control unit is connected to the two-way valve and the circulation pump. The internal circulation pipe functions to return a part of heated water back to the storage space to enhance thermal conversion efficiency and save energy and improve controllability. Positions for supplying cold water and returning water are made at different sites, and the circulation pump and the internal circulation pipe are used to selectively execute functions of anti-freezing, pre-heating, and heat balancing. An external circulation pipe is additionally included such that by means of the two-way valve and the circulation pump, switching can be made between internal and external circulations.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a heat exchanger, and more particularlyto an instantaneous-heating storage heat exchanger combined with smartcirculation control to enhance the thermal conversion efficiencythereof.

DESCRIPTION OF THE PRIOR ART

Referring to FIG. 5, a known tankless instant water heater 90 isstructured to heat a cold-water pipe 91 to a predetermined temperature.Due to a great difference of temperature between cold water and heatedwater, the consumption of energy is great and the control of temperatureis difficult, making it hard to supply a large quantity of heated waterin a very short period of time.

Further, the known instant water heater 90 includes, arranged in theinterior thereof, a coiled pipeline 92, which once being applied to anenlarged size, would not be effective for desired exchange of heat.Consequently, the size of the coiled pipeline 92 is subject toconstraint and cannot supply an increased quantity of heated watersimply by raising pressure.

Referring to FIG. 6, the known instant water heater 90 is additionallyprovided with a water circulation pipe 93. Although a cold-water inletport of the cold-water pipe 91 and an external water inlet port of thewater circulation pipe 93 seem different when observed from outside ofthe known instant water heater 90, the two are in fact set incommunication with each other in the interior of the known instant waterheater 90. Consequently, water circulation and water feed-out cannot beput into operation at the same time, as this would affect the control oftemperature.

Referring to FIG. 7, a different known water heater 80 has awater-circulating pre-heating system, which includes a pump 81 and anexternal circulation pipe 82. In practice, pre-heating is achieved bymeans of the pump 81 and the external circulation pipe 82.

In view of the above, the known water control configurations of waterheater require further improvements.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a smart circulationcontrol instantaneous-heating storage heat exchanger to enhance thermalconversion efficiency.

To achieve the above objective, the present invention comprises a heatexchanger, a cold-water pipe, a hot-water pipe, an internal circulationpipe, and a control unit, wherein the heat exchanger is arranged in aninterior of a water heater, the heat exchanger comprising a heat sourcesupply structure and a storage space, the heat source supply structureheating cold water contained in the storage space to convert into hotwater; the cold-water pipe is connected to the heat exchanger at a firstposition to supply cold water into the storage space; the hot-water pipeis connected to the heat exchanger at a second position to discharge thehot water generated in the storage space; the internal circulation pipeis disposed in the interior of the water heater, the internalcirculation pipe having two ends that are respectively connected to thehot-water pipe and the storage space to allow hot water contained in thehot-water pipe to return back to the storage space to enhance thermalconversion efficiency, the internal circulation pipe being combined witha two-way valve and a circulation pump; and the control unit isconnected to the two-way valve and the circulation pump to control apassage channel of the two-way valve to be in an open state or a closedstate and also to control a flow rate of the circulation pump.

The function and efficacy of the above heat exchanger are as follows:

(1) an arrangement that features both an instant device and a storage(tank involved) device, wherein since the storage has a large capacityof storage, heating can be made to a large quantity of water at the sametime and it is also possible to supply a large quantity of hot water,and increasing water discharge rate can easily made by simply expandinga water inlet port or a water outlet port; and

(2) location water introduction with a cold-water pipe being differentfrom location of water returning with an internal circulation pipe, suchthat temperature balance may be made inside the storage space for thecold water and the returned hot water, without affecting temperaturecontrol, and also allowing simultaneous operations for external pipepre-heating and water supplying.

The function and efficacy of the internal circulation pipe and thecirculation pump comprises are as follows:

(1) a part of discharged hot water being returned back to the storagespace to increase the temperature of cold water thereby reducing atemperature difference between the cold water and a preset temperatureand a desired temperature can be reached by heating with a loweredconsumption of energy, achieving high thermal conversion efficiency andsaving energy, and ease control of temperature due to reducedtemperature difference; and

(2) no external water circulation pipe being required, for the internalcirculation is sufficient for performance of pre-heating andanti-freezing functions and supplying of a large quantity of hot waterin a short period of time.

Another objective of the present invention is to provide a smartcirculation control instantaneous-heating storage heat exchanger, whichallows for selecting and switching between internal circulation andexternal circulation.

To achieve such another objective, the present invention furthercomprises an external circulation pipe, wherein two ends of the externalcirculation pipe are respectively connected to the hot-water pipe andthe internal circulation pipe.

By means of a control system formed of the two-way valve and the controlunit, switching of flow line between the internal circulation pipe andthe external circulation pipe can be made. In demand of hot water, thecontrol system switches to the internal-circulation-pipe flow line, sothat the internal circulation may be used to reduce a temperaturedifference and thus enhance thermal conversion efficiency, lowers energyloss, and reduces internal latent heat related phenomenon of the storagespace. In case of no hot water demand, the control system switches tothe internal-circulation-pipe flow line, so that the internalcirculation may be used for pre-heating and anti-freezing. Oralternatively, the control system switches to theexternal-circulation-pipe flow line, so that the external circulationmay provide functions of external circulation pipe pre-heating andanti-freezing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a first example of use of thepresent invention.

FIG. 2 is a block diagram illustrating a second example of use of thepresent invention.

FIG. 3 is a block diagram illustrating a third example of use of thepresent invention.

FIG. 4 is a cross-sectional view illustrating a storage space beingdivided into a high-temperature zone, a low-temperature zone, andmixed-temperature zone according to the present invention.

FIG. 5 is a diagram illustrating a first example of use of a knowninstant water heater.

FIG. 6 is a diagram illustrating a second example of use of the knowninstant water heater.

FIG. 7 is a diagram illustrating an example of use of another knowninstant water heater.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, the present invention comprises a heat exchanger10, a cold-water pipe 20, a hot-water pipe 30, an internal circulationpipe 40, and a control unit 50, of which details are provided below.

The heat exchanger 10 is arranged in an interior of a water heater 11.The heat exchanger 10 comprises a heat source supply structure 12 and astorage space 13. The heat source supply structure 12 is operable toheat and convert cold water contained in the storage space 13 into hotwater.

In the drawings, the wavy pattern hatching indicates water contained inthe storage space 13 and thicker and darker part of the hatchingindicates water having a relatively high temperature at such a location.

The cold-water pipe 20 is connected to the heat exchanger 10 at a firstposition in order to feed cold water into the storage space 13.

The hot-water pipe 30 is connected to the heat exchanger 10 at a secondposition in order to feed out hot water generated in the storage space13.

The internal circulation pipe 40 is disposed in the interior of thewater heater 11. The internal circulation pipe 40 has two ends that arerespectively connected to the hot-water pipe 30 and the storage space 13in order to return hot water contained in the hot-water pipe 30 back tothe storage space 13. The internal circulation pipe 40 is combined witha two-way valve 41 and a circulation pump 42.

The internal circulation pipe 40 functions to form aninternal-circulation-pipe flow line to realize internal circulation.

The control unit 50 is connected to the two-way valve 41 and thecirculation pump 42 in order to control a passage channel of the two-wayvalve 41 to be in an open state or a closed state and also to control aflow rate of the circulation pump 42.

Referring to FIG. 3, in an embodiment, the present invention may furthercomprise an external circulation pipe 60. The external circulation pipe60 has two ends that are respectively connected to the hot-water pipe 30and the internal circulation pipe 40 in order to selectively switch toan external-circulation-pipe flow line to realize external circulation.

With a control system so formed of the two-way valve 41 and the controlunit 50, switching the flow line between the internal circulation pipe40 and the external circulation pipe 60.

Referring again to FIG. 1, in an embodiment, the heat source supplystructure 12 comprises an air blower 121, a burner 122, and a heatexchange pipe 123. The air blower 121 supplies a fuel gas and air intothe burner 122 for burning to generate a heat source. The burner 122generates combusted gas that enters the heat exchange pipe 123 to allowthe heat exchange pipe 123 to heat water contained in the storage space13.

In an embodiment, a temperature sensor 43 is mounted to a part of theinternal circulation pipe 40 located between the two-way valve 41 andthe circulation pump 42. The temperature sensor 43 is connected to thecontrol unit 50, so that a water temperature sensed by the temperaturesensor 43 is transmitted to the control unit 50 to allow the controlunit 50 to signal and thus control and regulate the flow rate of thecirculation pump 42 or to control and regulate a heating value providedby the heat source supply structure 12.

In an embodiment, the control unit 50 may be a controller including acontrol circuit board that enables setting of parameters andinstructions for signaling and thus controlling the two-way valve 41 andthe circulation pump 42.

In an embodiment, the connection of the cold-water pipe 20 to the heatexchanger 10 is provided, at the connection site at first position, witha water inlet connector 21, which eases mounting/removing andreplacement of the cold-water pipe 20; the connection of the hot-waterpipe 30 to the heat exchanger 10 is provided, at the connection site atthe second position, with a hot-water connector 31, which easesmounting/removing and replacement of the hot-water pipe 30; and theconnection of the internal circulation pipe 40 to the storage space 13is provided, at the site of connection, with a circulation connector 44,which eases mounting/removing and replacement of the internalcirculation pipe 40.

The above provides a description to the parts/components of the presentinvention and the assembly thereof, and in the following, examples ofuse, features, and advantages of the present invention will bedescribed.

Referring to FIG. 1, in a state that the water heater 11 is in operationto supply hot water for daily living (where no outside-arranged externalcirculation pipe is involved):

cold water flows through the water inlet connector 21 into the heatexchanger 10 and is subject to heat exchange inside the storage space 13to provide hot water, which is discharged from the hot-water connector31.

In a condition of continuous supply of hot water, the control systemmade up of the two-way valve 41 and the control unit 50 switches or setsthe two-way valve 41 to an internal circulation mode, in which theinternal circulation pipe 40 is opened and the circulation pump 42 iskept in continuous operation to cause hot water to flow at a rate of 1-5liters per minute through the circulation connector 44 to return backinto the heat exchanger 10, such that cold water contained in thestorage space 13 is mixed with the hot water so returned to cause riseof temperature, wherein the temperature sensor 43 senses the rise ofinternal temperature of the storage space 13, indicating there is noextra supply of thermal energy, with which automatic regulation andreduction of the supply of thermal energy is made.

Referring to FIG. 4, when the external demand for water is terminated,the internal circulation mode that is established with the flow lineinvolving the circulation pump 42 and the internal circulation pipe 40maintains operation for a period of 30 second, so that during such aperiod, temperatures of a high-temperature zone 131 and alow-temperature zone 133 inside the storage space 13 are mixed uniformlyto form a mixed-temperature zone 132, which helps prevents concentrationof thermal stress caused by latent heat of the high-temperature zone 131on an upper portion of the heat exchanger 10 to cause latent heatdeformation in the material of the heat exchanger 10, which destructsstructural stiffness and affects the durability thereof.

Referring to FIG. 2, in a state that the water heater 11 is kept stilland in an idle condition, where no outside-arranged external circulationpipe may be involved, the two-way valve 41 can be selectively switchedto the internal circulation configuration.

Referring to FIG. 3, the water heater 11 is kept still and in an idlecondition, but with the external circulation pipe 60 involved, thetwo-way valve 41 can be selectively switched to the external circulationconfiguration.

In the internal circulation configuration and the external circulationconfiguration respectively shown in FIGS. 2 and 3, the present inventioncan be selectively set at the following mode:

(1) Anti-freezing mode (5° C.): the internal circulation or the externalcirculation is kept at a non-freezing temperature.

Activation of heating in anti-freezing mode=the temperature sensor 43sensing temperature being persistently lower than 5° C. for a period of10 seconds, and the internal circulation or the external circulationactivated to perform heating with a minimum required level of energy.

Deactivation of heating in anti-freezing mode=anti-freezing temperature(which is set for a default value of 5° C.)+increase of temperature(which is set for a default value of 5° C.).

(2) Pre-heating mode: the internal circulation or the externalcirculation maintains at a temperature of hot water sufficient for dailyliving.

Activation of heating in pre-heating mode=the temperature sensor 43sensing temperature being persistently lower than a pre-heatingactivation setting value for a period of 10 seconds, and the internalcirculation or the external circulation activated for operation andperforming heating with a minimum required level of energy.

Deactivation of heating in pre-heating mode=daily living hot watertemperature setting value+increase of temperature (which is set for adefault value of 0° C.).

(3) Energy-saving mode: the internal circulation or the externalcirculation maintains daily living water supply at a normal or roomtemperature.

Activation of heating in energy-saving mode=the temperature sensor 43sensing temperature being persistently lower than an energy-savingactivation setting value (which is set for a default value of 25° C.)for a period of 10 seconds, and the internal circulation or the externalcirculation activated for operation and performing heating with aminimum required level of energy.

Deactivation of heating in energy-saving mode=energy-saving temperaturesetting value (which is set for a default value of 30° C.)+increase oftemperature (which is set for a default value of 0° C.).

When there is a demand for hot water for daily living in a conditionwhen the present invention is set in the anti-freezing mode, thepre-heating mode, or the energy-saving mode, the present inventionautomatically switches to a condition of supply, as priority, hot waterfor daily living.

In a preferred operation, the above-described anti-freezing,pre-heating, and energy-saving modes of the present invention isselectively activated by just one among the others.

I claim:
 1. A smart circulation control instantaneous-heating storageheat exchanger, comprising: a heat exchanger, which is arranged in aninterior of a water heater, the heat exchanger comprising a heat sourcesupply structure and a storage space, wherein the heat source supplystructure heats cold water contained in the storage space to convertinto hot water, a cold-water pipe, which is connected to the heatexchanger at a first position to supply cold water into the storagespace; a hot-water pipe, which is connected to the heat exchanger at asecond position to discharge the hot water generated in the storagespace; an internal circulation pipe, which is disposed in the interiorof the water heater, the internal circulation pipe having two ends thatare respectively connected to the hot-water pipe and the storage spaceto allow hot water contained in the hot-water pipe to return back to thestorage space to enhance thermal conversion efficiency, the internalcirculation pipe being combined with a two-way valve and a circulationpump; and a control unit, which is connected to the two-way valve andthe circulation pump to control a passage channel of the two-way valveto be in an open state or a closed state and also to control a flow rateof the circulation pump.
 2. The smart circulation controlinstantaneous-heating storage heat exchanger according to claim 1,further comprising an external circulation pipe, the externalcirculation pipe having two ends that are respectively connected to thehot-water pipe and the internal circulation pipe to selectively switchto an external-circulation-pipe flow line to realize externalcirculation, such that a control system formed of the two-way valve andthe control unit is operable to switch a flow line between the internalcirculation pipe and the external circulation pipe.
 3. The smartcirculation control instantaneous-heating storage heat exchangeraccording to claim 1, wherein the heat source supply structure comprisesan air blower, a burner, and heat exchange pipe, wherein the air blowersupplies a fuel gas and air to the burner for burning to generate heat,combusted gas generated in the burner and entering the heat exchangepipe to allow the heat exchange pipe to heat the cold water contained inthe storage space.
 4. The smart circulation controlinstantaneous-heating storage heat exchanger according to claim 1,wherein a temperature sensor is mounted to the internal circulation pipebetween the two-way valve and the circulation pump, and the temperaturesensor is connected to the control unit, so that a water temperaturesensed by the temperature sensor is transmitted to the control unit toallow the control unit to control and regulate a flow rate generated bythe circulation pump or to control and regulate a heating value providedby the heat source supply structure.
 5. The smart circulation controlinstantaneous-heating storage heat exchanger according to claim 1,wherein the control unit comprises a controller including a controlcircuit board that enables setting of parameters and instructions forcontrolling the two-way valve and the circulation pump.
 6. The smartcirculation control instantaneous-heating storage heat exchangeraccording to claim 1, wherein the connection of the cold-water pipe tothe heat exchanger comprises a water inlet connector installed at thefirst position to ease mounting and assembling and replacement of thecold-water pipe; the connection of the hot-water pipe to the heatexchanger comprises a hot-water connector installed at the secondposition to ease mounting and assembling and replacement of thehot-water pipe; and the connection of the internal circulation pipe tothe storage space comprises a circulation connector installed at aconnection site thereof to ease mounting and assembling and replacementof the internal circulation pipe.
 7. The smart circulation controlinstantaneous-heating storage heat exchanger according to claim 2,wherein the heat source supply structure comprises an air blower, aburner, and heat exchange pipe, wherein the air blower supplies a fuelgas and air to the burner for burning to generate heat, combusted gasgenerated in the burner and entering the heat exchange pipe to allow theheat exchange pipe to heat the cold water contained in the storagespace.
 8. The smart circulation control instantaneous-heating storageheat exchanger according to claim 2, wherein a temperature sensor ismounted to the internal circulation pipe between the two-way valve andthe circulation pump, and the temperature sensor is connected to thecontrol unit, so that a water temperature sensed by the temperaturesensor is transmitted to the control unit to allow the control unit tocontrol and regulate a flow rate generated by the circulation pump or tocontrol and regulate a heating value provided by the heat source supplystructure.
 9. The smart circulation control instantaneous-heatingstorage heat exchanger according to claim 2, wherein the control unitcomprises a controller including a control circuit board that enablessetting of parameters and instructions for controlling the two-way valveand the circulation pump.
 10. The smart circulation controlinstantaneous-heating storage heat exchanger according to claim 2,wherein the connection of the cold-water pipe to the heat exchangercomprises a water inlet connector installed at the first position toease mounting and assembling and replacement of the cold-water pipe; theconnection of the hot-water pipe to the heat exchanger comprises ahot-water connector installed at the second position to ease mountingand assembling and replacement of the hot-water pipe; and the connectionof the internal circulation pipe to the storage space comprises acirculation connector installed at a connection site thereof to easemounting and assembling and replacement of the internal circulationpipe.